<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Vue 测试实例 - 菜鸟教程(runoob.com)</title>
<script src="https://cdn.staticfile.org/vue/3.2.36/vue.global.min.js"></script>
</head>

<body>
<div id="hello-vue" class="demo">
  <h1>{{count}}</h1>
  <button @click="count++">click</button>

</div>

<script>
var app = {
  data(){
    return {
      count : 1
    }
  }
}

var vm =  Vue.createApp(app).mount('#hello-vue')

vm.$watch('count',function(New, Old){
  console.log("New:",New)
  console.log("Old:",Old)
})

</script>
</body>
</html>
